Open Journal of Stomatology, 2013, 3, 452-456 OJST Published Online November 2013 (
Radiographic study of the root canal system of mandibular
incisors in Palestinian population
Raed Mukhaimer, Maher Jarbawi
Department of Conservative Dentistry, Arab American University, Jenin, Palestine
Received 9 October 2013; revised 10 November 2013; accepted 20 November 2013
Copyright © 2013 Raed Mukhaimer, Maher Jarbawi. This is an open access article distributed under the Creative Commons Attribu-
tion License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
Aim: The aim of this study was to survey the root
canal morphology of mandibular incisor teeth in a
Palestinian population using radiographic approach.
Materials and Methods: Five hundred and twenty
two extracted mandibular incisor teeth were randomly
collected from Palestinian population. The teeth were
radiographed from a mesiodistal direction and ex-
amined for the presence of a second canal and for the
type of canal configuration. Results: All teeth had sin-
gle root. Three hundred and sixty nine teeth (70.7%)
had one canal (type I Vertucci classification). The rest
(29.3%) had a second canal (type II and III). Conclu-
sion: Mandibular central and lateral teeth were most-
ly found to have one root and Type I canal system.
Keywords: Mandibular Incisors; Radiography; Root
Canal System
Successful outcomes of endodontic treatment depend on
the identification of all root canals which in turn guaran-
tee complete extirpation of pulp tissue, proper chemo-
mechanical cleaning and shaping and three dimensional
obturation of the root canal system with an inert filling
material. Undetected extra roots or root canals had been
considered as a major reason for failure of root canal
treatment [1].
Many of the challenges faced during root canal treat-
ment may be directly attributed to an inadequate under-
standing of the canal morphology of teeth. Studies had
shown that anatomical variations can occur in all groups
of teeth with different incidences with respect to number
of roots and root canals and with respect to root/canal
system configuration [2-4].
Different techniques had been used to study the root
canal anatomy of the mandibular incisors. Vertucci [2]
used the clearing technique to study the root canal mor-
phology of 300 extracted mandibular incisors and found
that two canals were present in 30% of mandibular cen-
tral incisors and in 25% of mandibular lateral incisors.
Using the same technique, Miyashita et al. reported that
more than 85% of root canals possessed a single canal
[5]. Mauger et al. [6] used root sectioning to assess the
canal anatomy at different root levels in 100 lower inci-
sors and reported that 98% - 100% of the teeth had one
canal in the area situated 1 - 3 mm above the apex.
In a study conducted in Iranian population using
Cone-Beam Computed Tomography, 632 central incisors
and 614 lateral incisors were examined. A second canal
was found in 27.3% of central incisors and 29.4% of
lateral incisors [7]. De Oliveira et al. [8] used digital ra-
diography to analyze the presence of an extra canal in
lower incisors. The in vitro study was conducted on 200
mandibular incisors positioned on a model, simulating
the mandibular dental arch. Digital radiographs were
taken from the mandibular incisors in both buccolingual
and mesiodistal directions. The digital radiography
showed presence of bifurcation in 20% of teeth evaluated
in the mesiodistal direction. In the buccolingual direction,
15% presented bifurcation or characteristics indicating
It had been reported that root canal systems of man-
dibular incisors may vary according to race. In his study,
in Southern Chinese population, Walker had found that
28% of mandibular incisors possess two separate canals
[9]. Boruah and Bhuyan [10] reported an incidence of
36.25% of the roots possessed two canals in a population
of North East India. Sert et al. investigated the root canal
configurations of mandibular permanent teeth in Turkish
population and r epo r ted th e presence of a second canal in
68% of mandibular central incisors and 63% of lateral
incisors [11].
No data are available on the root canal morphology of
R. Mukhaimer, M. Jarbawi / Open Journal of Stomatology 3 (2013) 452-456 453
mandibular incisors in Palestine. The aim of the present
investigation was to find out the incidence of second root
canal and the type of root canal configuration of man-
dibular incisors amongst Palestinian population.
Five hundred and twenty two extracted mandibular inci-
sors were randomly collected from several private dental
clinics. The Ministry of Health Ethics Committee ap-
proved the study. All individuals agreed to participate by
signing an informed consent form. No attempt was made
to differentiate between central and lateral incisors. All
teeth included in the study had intact clinical crowns and
fully-formed roots. The teeth were cleaned from any re-
maining calculus and soft tissue by scaling and washed
with tap water and then placed in 10% formalin solution.
Teeth were arranged in a group of three over one
X-ray film (Ektaspeed Plus, Eastman Kodak, Rochester,
NY,USA) and radiographed in a mesiodistal direction
using paralleling technique. Time was set to 0.1 second.
To minimize variations, target film distance was kept to 5
cm. The X-rays were developed according to the manu-
facturer instructions.
The resultant images were examined by the author for
the presence of a single root canal or bifurcated root ca-
nal. All radiographs were examined systematically in a
darkened room using an illuminated viewer box with
magnification (2.5×).The configuration of each canal
was also categorized into the first four types of Vertucci’s
classification 2 as follows:
Type I: single canal is present from the pulp chamber
to the apex
Type II: two separate canals leave the pulp chamber
but join short of the apex to form one canal
Type III: one canal leaves the pulp chamber but di-
vides into two within the body of the root canals then
merge again to exit as one canal
Type IV: two separate canals are present from the pulp
chamber to the apex
The four canal configurations are shown in Figure 1.
All examined central and lateral incisors had only a sin-
gle root. The results are summarized in Table 1 that
shows the number and percentages of each canal type in
mandibular incisors. Of the 522 teeth studied, the major-
ity (70.7%) displayed a type I root canal configuration,
type II was found in 16.3 % cases and typ e III in 13%. An
overall of one hundred and fifty three teeth (29.3%) pos-
sessed a second canal. Figures 2, 3 and 4 show samples
of the radiographs representing Vertucci’s canal configu-
ration type I, II, and III respectively.
Figure 1. Vertucci root canal classification.
Table 1. number and percentages of mandibular incisor
teeth with various types canal configuration based on Ver-
tucci’s classification.
Canal configuration number of teeth (%)
Type I (1 - 1) 369 (70.7% )
Type II (2 - 1) 85 (16.3%)
Type III (1 - 2 - 1) 68 (13.0%)
Type IV (2 - 2) 0 (0%)
Total 522 (100%)
Figure 2. Selected radiograph of single canal (type I) of
mandibular incisors.
Copyright © 2013 SciRes. OPEN ACCESS
R. Mukhaimer, M. Jarbawi / Open Journal of Stomatology 3 (2013) 452-456
Figure 3. Selected radiograph of two canals (type II) of
mandibular incisors.
Figure 4. Selected radiograph of two canals (type III) of
mandibular incisors.
A variety of techniques have been used to study the in-
ternal anatomy of lower incisors [5,6,8]. Although radi-
ography is unlikely to show the complexities of the root
canal system such as lateral canals and eccentrically lo-
cated apical foramina [12], it may demonstrate the main
anatomical features. Hence the present study aimed to
investigate the incidence of bifurcated canals and the
type of canal configuration, this technique was used in
this study and the examined teeth were radiographed in a
mesiodistal direction. Radiographs may be the only non-
invasive means clinically to provide clues about the
morphology of the root canal system. This technique
proved to be simple and fast and needs little equipment.
Successful root canal therapy depends on sound know-
ledge of the normal and abnormal internal anatomy of
the treated tooth. Investigators have shown multiple fo-
ramina, loops, fins, deltas, additional canals, accessory
canals, intercanal connections and “C-shaped” canals.
Consequently the practitioner must treat each tooth as-
suming that complex anatomy oc curs often enough to be
considered normal.
Mandibular incisors have been traditionally treated as
teeth with a single canal. Anatomical studies had shown
that a considerable percentage of mandibular incisors
ranging between 12.4% [5] and 68% [11] posses a den-
tinal bridge in the pulp chambe r that divides the roo t into
two canals. The two canals usually join and exit through
a single apical foramen, but they may persist as two
separate canals.
Vertucci [2] examined the root canal morphology of
300 mandibular anterior teeth and reported a second ca-
nal in 27.5% of mandibular incisors. Al-Qudah and Aw-
awdeh [13] examined the root canal morphology of 450
mandibular anteriors in Jordanian population and re-
ported a second canal in 26.2% of mandibular incisors. A
higher incidence (36.25%) was reported by Boruah and
Bhuyan [14] who investigated the root canal anatomy of
mandibular incisors of North East Indian population. In a
recent study conducted by Al-Fouzan et al, 30% of man-
dibular incisors of Saudi population were found to have a
second canal [15]. The differences between these mor-
phology studies may be related to variations of examina-
tion techniques, sample size, classification systems and
ethnic background of tooth sources.
In the present study, 29.3% of the mandibular incisors
possessed a second root canal. All of these canals joined
and exited in a single foramen (Type II and III). The fre-
quency of two canals in the present study was within the
range of previous reports and very close to the frequent-
cies reported in the Middle East region (26.2% in Jorda-
nian population, 30% in Saudi population and 28.3% in
Iranian population).
Copyright © 2013 SciRes. OPEN ACCESS
R. Mukhaimer, M. Jarbawi / Open Journal of Stomatology 3 (2013) 452-456 455
The results of this investigation indicate th at about one
third of lower incisors in Palestinian population has a
second canal. The clinicians should always take this
anatomical variation into consideration when treating
this group of teeth as this relatively high proportion is
not routinely found during clinical procedure. Clinicians
usually fail to recognize the presence of a second canal
either due to lake of knowledge of root canal morphol-
ogy or due to lake of experience and skills to negotiate
that canal [16] with a subsequent failure of root canal
To overcome the challenge of locating the second ca-
nal and optimize the access preparation, the traditional
lingual access of lower anteriors had been modified by
extending the access toward the cingulum [17]. With the
invention of highly aesthetic restorative materials, some
authors had suggested labial or incisal approach for
mandibular incisors as an alternative approach of lingual
access [18,19].
For several reasons, the clinician should not feel se-
cure when treating only one canal. An important poin t is
that, the two canals in lower incisors, if present, usually
join 1-3 mm from the apex. If one canal is prepared and
filled shorter from this joining point, the second canal
will become necrotic and open directly into the periapi-
cal area through the apical foramen [20]. Another point is
that, when only one canal is treated, pulp tissue in the
second canal can ultimately release harmful substances
through a secondary canal to the interior space of the
periodontium ligament [21]. In both situations, a subse-
quent failure of root canal treatment may occur.
Based on the findings of this study, a high incidence of
two canals in the lower incisor teeth had been found in
Palestinian population. Th e clinician must be alert for the
possibility of a b ifurcated root canal in these teeth as th is
may complicate root canal treatment.
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